Suppose i have created a table BOOKSHELF

create table BOOKSHELF (Title VARCHAR2(100) primary key, Publisher VARCHAR2(20), CategoryName VARCHAR2(20), Rating VARCHAR2(2), constraint CATFK Foreign Key (CategoryName)references CATEGORY(CategoryName));

and now i assign a non-unique index to CategoryName

create index IBOOKSHELFCATEGORY on BOOKSHELF(CategoryName);

Therefore we can say now there are two indexes on the BOOKSHELF table one is implicitly created primary key unique type index on Title column and other is explicitly assign non-unique type index on CategoryName column.

Now if i say

select * from BOOKSHELF where Title!='INNUMERACY';

so my question is

Does the optimizer perform index scan or it perform full table scan? why?.....PLZ EXPLAIN IN DETAIL CONSIDERING SAME EXAMPLE...........